Cheap-Thermocam Gets an Impressive Rehaul

[Max Ritter] is a 21 year old student of information technology at the University of Applied Science at Weingarten, Germany. Three years ago he brought us the DIY Cheap-Thermocam, a tool for thermal imaging that cost <$100. Since then he’s made a few upgrades.

The original Cheap-Thermocam made use of an Arduino, the sensor from a thermometer gun and a few XY servos. In about 2 minutes the XY servos can scan and measure 1344 points using the thermometer’s sensor, creating a heat-vision map of 42 x 32 pixels — not amazing, but it worked — and it was cheap!

The new version (V3) has its own ARM Cortex M3 processor, it measures 3072 points in 2 minutes from -70°C to 380°C with an accuracy of 0.5°C, and it exports its images at a resolution of 640 x 480 –close to commercial offerings! It’s not capable of real-time scanning, but for the majority of purposes you need one of these for — it’s really not that necessary.

This type of scanning-type IR imaging is a very interesting approach for large objects.
With the scanning action, you can get high-resolution images of larges objects, where one pixel corresponds to a relatively big spot on the object.

However, for many applications you need medium-high resolution images of small objects – like SMD parts on a PCB or wires in an electrical installation.

And then it looks like this scanning-type camera is not useful. The minimum spot size is just too large.

There are two spot sizes I’m aware of for IR thermometers. One is 1:8 and a smaller 1:12. It is a ratio of the size of the spot to the distance from the thermometer. So a 1:12 unit could be tried.

One other thing that could be tried is an iris blocker, make it like a pinhole camera. If it can be done, it would narrow down the spot size and allow increased resolution. The scan time and resolution are related, so expect a longer measurement time for the more data points measured.

Makes sense since the problem with the cheap scan is that there is a minimum time to take a reading, and if you increased resolution 100 times it would also increase the time 100 times. And the time issue is not the MCU but the sensor.

That is awesome. It could be possibly made more like those fancy FLIR cameras if he put a mirror on a servo and have the servo move to put the ir senor or the webcam inline with the object so that the images could be stacked with little offset. Just a thought.